Regional variability in East Antarctic surface accumulation over the past 162 kyr inferred from englacial stratigraphy at the southern flank of Dome A

Abstract. Accurate reconstructions of past surface mass balance are critical for understanding Antarctic Ice Sheet evolution. Ice cores can provide valuable records of surface mass balance history, but individual core sites may not fully capture regional variability. In this study, we infer the surface mass balance history along the southern flank of Dome A, East Antarctica, with recently acquired englacial radiostratigraphy. We first estimate the average accumulation rate for the past 4.9 kyr. We then use a 2.5-D flowband model constrained by eight dated englacial horizons from 4.9 ka to 161.9 ka to infer temporal variations in the surface mass balance history. We find that applying the normalized temporal accumulation history from the EPICA Dome C (EDC) ice core leads to a substantial mismatch between modeled and observed englacial stratigraphy along the southern flank of Dome A. To match the observed stratigraphy within the range of uncertainties, the model requires accumulation rates approximately 5 %–33 % higher than EDC-derived values between 10.9 and 40.8 ka, 30 %–98 % higher between 40.8 and 87.9 ka, and 18 %–38 % lower between 87.9 and 161.9 ka. Accumulation histories derived from individual deep ice cores, while valuable, may not fully represent the spatial and temporal variability across different sectors of Antarctica. This work underscores the need to combine ice-core chronologies, radar-derived stratigraphy, and ice-flow modeling to build regionally appropriate reconstructions of climate history.